US President Donald Trump heads to Japan on the first stop of his 12-day, five-nation tour of Asia on Saturday, looking to present a united front with the Japanese against North Korea as tensions run high over Pyongyang’s nuclear and missile tests.

Trump is to speak to US and Japanese forces at Yokota airbase soon after arriving in Japan on Sunday and will stress the importance of the alliance to regional security.

Aerial drills conducted over South Korea by two US strategic bombers have raised tensions in recent days.

In a display of golf diplomacy, Trump is to play a round with Japan’s Prime Minister Shinzo Abe. The two leaders played together in Florida earlier this year.

Trump will meet the Imperial Family at Akasaka Palace. Abe and Trump will also visit families of Japanese citizens abducted by North Korea.

Joined by his wife Melania on part of the trip, Trump’s tour of Asia is the longest by an American president since George H.W. Bush in 1992. Besides Japan, he will visit South Korea, China, Vietnam and the Philippines.

Trump extended the trip by a day on Friday when he agreed to attend a summit of East Asian nations in Manila.

His trip got off to a colourful start in Hawaii. He was taken by boat out to the USS Arizona Memorial, where lies the second world war ship that was sunk by the Japanese during the Pearl Harbour attack in 1941.

Trump’s trip is to be dominated by trade and how to muster more international pressure on North Korea to give up nuclear weapons.

“We’ll be talking about trade,” Trump told reporters at the White House on Friday. “We’ll be talking about obviously North Korea. We’ll be enlisting the help of a lot of people and countries and we’ll see what happens. But I think we’re going to have a very successful trip. There is a lot of good will.”

Trump has rattled some allies with his vow to “totally destroy” North Korea if it threatens the US.

North Korea ruled out talks and threatened to increase its nuclear arsenal in a fresh warning to Trump’s administration on Saturday.

The North’s state-run KCNA news agency said in a commentary that the US should be disabused of the “absurd idea” that Pyongyang would succumb to international sanctions and give up its nuclear weapons, adding that it is in “the final stage for completing nuclear deterrence”.

“It had better stop daydreaming of denuclearisation talks with us,” said the commentary titled “Stop dreaming a daydream”.

“Our self-defensive nuclear treasure sword will be sharpened evermore unless the US hostile policy ... is abolished once and for all,” it said.

Trump will seek a united front with the leaders of Japan and South Korea against North Korea before visiting Beijing to make the case to President Xi Jinping that he should do more to rein in Pyongyang.

Trade will factor heavily during Trump’s trip as he tries to persuade Asian allies to agree to trade policies more favourable to the US.

A centrepiece of the trip will be a visit to the Asia Pacific Economic Cooperation summit in Danang, Vietnam, where he will deliver a speech in support of a free and open Indo-Pacific region, which is seen as offering a bulwark in response to expansionist Chinese policies.